A very very large large crap left in a high school bathroom or next to a fallen tree. Typically in the shape of a right angle. To make an official jorgenbar, one must not wipe in the same stall but in the one next to it...thus preserving the bar for future stundents to admire!
Serious straining required!

the whale tail is the shape formed when a g-string rides up high over a womans trousers